Spiral roll



R. GREINER Dec. 19, 1961 United States i atent if) 3,013,386 SPIRAL RGLL Rudolf Greiner, Eichenweg 14, Langenthal, Switzerland Filed Mar. 7, H61, Ser. No. 93,934 Claims priority, application Switzerland July 1, 196% 4 Claims. ((Il. 58--l15) This invention relates to a spiral roll and more particularly to a spiral roll for the kink-free attachment of the spiral spring of an oscillating system intended for clockworks, said spiral roll comprising a mounting hole for placing the spiral roll over the balance wheel shaft of the oscillating system, a curved supporting surface for the inner end piece of the spiral spring as well as a releasing edge which terminates the curved supporting surface and after which the spiral spring extends according to its natural shape at a spacing from the spiral roll.

Objects of the invention are to provide a spiral roll of the type stated in which the curved supporting surface is formed by a circular cylindrical surface, the axis of the mounting hole being parallel to the axis of the cylindrical surface and passing through the third or fourth quadrant of a right-angled system of co-ordinates which extends in a plane normal to the axis of said cylindrical supporting surface, the origin of which lies in the axis of the supporting surface, the x axis of which extends through the releasing edge, and the quadrants of which are counted from the releasing edge in the same sense in which the spiral spring to be fixed to the spiral roll becomes wider, and further in that the spacing of the axis of the mounting hole from the x axis of the system of co-ordinates amounts to at least substantially /211- times the pitch of the spiral spring to be connected to the spiral roll. In a preferred construction of the spiral roll according to the invention, the axis of the mounting hole passes through the third quadrant of the said system of co-ordinates and in addition has a spacing from the y axis thereof which is no more than half the pitch of the spiral spring to be fixed to the spiral r011. In this case it is desirable that the circular cylindrical supporting surface is formed only in the second and fourth quadrants of the system of coordinates x, y and is interrupted by recesses extending in the first and third quadrants of the system of co-ordinates, one of these recesses being located to adjoin the said releasing edge. Such a circular cylindrical supporting surface can to advantage be constituted by a channel formed in the spiral roll.

These and other objects and the advantages of the invention will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawing in which:

:FIG. 1 is a sectional view through the spiral roll and the inner portion of a spiral spring fixed thereto without kinks, taken through a plane 1-1 in FIG. 2 passing through the axis of the mounting hole, and

FIG. 2 is a cross-sectional view corresponding to FIG.

1 taken on a plane 2-2 in FIG. 1 normal to the axis of the mountinghole.

The spiral roll R, the shape of which will be described in detail hereinafterpis provided with a groove or channel N the base of which serves as a supporting surface F for the spiral spring S which is to be inserted in this groove N. The supporting surface 1 is of circular cylindrical formation and has the axis of curvature f. The height of the groove N is such that the spiral spring S can be inserted without jamming and can be retained therein practically without play in the direction of the axis 1''. This achieves that the spiral spring S extends in planes normal to the axis f. The depth of the groove or channel N is preferably somewhat larger than the thickness of the spiral spring S, as shown in Patented Dec. 19, 1961 FIG. 1. By means of a radially inward cut and an adjoining recess G, a releasing edge K is formed which, according to FIG. 2, terminates the circular cylindrical supporting surface P and thereby also the groove N. The recess G is so dimensioned that a spiral spring S inserted in the groove N can extend according to its natural shape after the releasing edge K, the adjoining spiral turns being spaced from the spiral roll R as shown in FIG. 2.

For a further description of the spiral roll R accord ing to the invention, it is best to introduce a right-angled system of co-ordinates x, y in FIG. 2, which system extends in a plane normal to the axis 1 of the supporting surface F. The origin of the system of co-ordinates x, y should lie in the axis 1 of the supporting surface F. Further, the x axis of the system of co-ordinates x, y

extends through the releasing edge K. The quadrants defined by the axes x, y are indicated in FIG. 2 by Roman numerals I, II, III, IV. The quadrants are counted anti-clockwise from the releasing edge K because the spiral spring S to be placed on the spiral roll R also widens in a counter-clockwise sense.

Now, in order to ensure that the spiral spring S can extend counter-clockwise without kinks from the releasing edge K and according to its natural shape at a spacing form the spiral roll R, a specially eccentric arrangement of the mounting hole B is provided by means of which the spiral roll R is placed on the balance wheel shaft. As usual, this mounting hole is slightly conical (FIG. 1). The axis of curvature b of the mounting hole B is so arranged that it extends parallel to the axis 1 of the supporting surface F and passes through the third or fourth quadrant of the system of co-ordinates x, y. The axis b of the mounting hole 13 should have a spacing from the x axis which is at least substantially equal to /21r times the pitch of the spiral spring S to be fixed to the spiral roll R. As usual, the pitch of the spiral spring S is to be understood to mean the constant growth of the radius vector of Archimedes spirals during a complete turn of the spiral. In the first instance, the point at which the axis b of the mounting hole B passes through the third or fourth quadrant of the system of coordinates x, y is of secondary importance; what is much more critical is the maintenance of the said spacing of the axis b of the mounting hole B from the x axis which, when multiplicated by 271" is to be equal to the pitch of the spiral spring S which is to be mounted. The spiral spring S itself is inserted in the groove N of the spiral roll R in such a way that the radius vector of the spiral spring S at the location of the releasing edge K is equal to the spacing between the releasing edge K and the axis b of the mounting hole B. The inner end piece of the spiral spring S is then brought to lie on the circular cylindrical supporting surface F commencing from the releasing edge K, Le. in the adjoining region of the fourth quadrant. Without any other procedure, all of the spiral spring S freely extending counter-clockwise from the releasing edge K will then be accurately centered or, in other words, its origin will come to lie in the axis b of the mounting hole B. At the releasing edge K itself, the tangent to the cylindrical surface F and the tangent to the spiral spring S coincide sothat the formation of a kink is unnecessary.

The desired accuracy of mounting and centering of the spiral spring S by means of the circular surface F will, however, be achieved only if the radius of the circular cylindrical supporting surface F does not differ too much from the natural radius of curvature of the spiral spring S at the location of the releasing edge K. If the axis b of the mounting hole B is displaced to pass through the fourth quadrant then the radius of curva-.

ture of the inserted spiral spring S under the above con- (3 ditions becomes smaller than the radius of the supporting surface P. However, if the axis b passes through the third quadrant in accordance with FIG. 2, then, analogously, the said radius of curvature of the spiral spring S is larger than the radius of the supporting surface F. Finally, if the axis b extends through the y axis of the system of coordinates x, y, then the natural radius of curvature of the spiral spring S at the releasing edge K is the same as the radius of the supporting surface F. Now, it has been found that acceptable conditions are obtained if the axis b of the mounting hole B is spaced from the y axis no more than half the pitch of the spiral spring S, the axis b being permitted to pass through the third or fourth quadrant. However, as already explained above, it is necessary that the radius vector of the spiral spring S at the location of the releasing edge K be made equal as the relevant spacing between the releasing edge K and the axis b of the mounting hole B.

The more precise choice of the eccentric arrangement of the axis b in relation to the circular cylindrical supporting surface F within the above-rncntioned limits is primarily determined by manufacturing considerations. For the correct mounting and centering of the spiral spring S it would suilice if the circular surface F extends from the releasing edge K into the fourth quadrant of the system of co-ordinates x, y only so far as appears necessary for secure mounting of the end piece of the spiral spring S in the groove N of the spiral roll R. However, during this mounting, care should be taken that the end piece of the spiral spring S lies well against the base of the groove -N at all points. Directly before and during fixing of the spiral spring S to the spiral roll R there should therefore be used appropriate operations and tools which ensure that the end piece of the spiral spring S lies on the supporting surface F.

According to a further development of the invention, these additional operations and tools can be avoided if the circular cylindrical supporting surface 'F is formed in the second quadrant as well as in the fourth quadrant and is interrupted by recesses G and H extending in the first and third quadrant as shown in FIG. 2. The inner end piece of the spiral spring S extending clockwise from the releasing edge K can then have a looping angle of over 180 and will automatically press against the base of the groove N and thereby against the supporting surface F by virtue of its resiliency. in this case it is, of course, a prerequisite that the radius of the supporting surface F has such a relation to the radius of curvature of the spiral spring S at the location of the resleasing edge K that the end piece of the spiral spring S must be slightly spread out in order to bring it into the FIG. 2 position. On the other hand, there are limits to the radius of the supporting surface F in that the surface F formed in the second quadrant must be radially spaced from the next following free spiral turn of the spring S sufficient to avoid contact with the latter. Now, all these requirements can be fulfilled only if the axis b of the mounting hole B passes through the third quadrant and has a spacing from the y axis of the system of co-ordinates x, y which is no larger than half the pitch of the spiral spring S. Favourable conditions are obtained according to FIG. 2 if the spacing of the axis b from the y axis is chosen to be one-third of the pitch of the spiral spring S.

In addition, the supporting surface F formed only in the second and fourth quadrant of the system of coordinates x, y makes it possible to balance the spiral roll R by suitably shaping the recesses G and H in relation to the axis b of the mounting hole B. However, the accurate formation of the recesses G, H and the surface qualities of spiral roll R are not critical at the location of the recesses. It is merely necessary to be accurate when forming the circular cylindrical suppering surface F and the mounting hole B with the prescribed eccentric displacement of its axis b. For this purpose, conventional automatic lathes can be used.

The invention is not limited to the particular embodiment here shown and described. Various modifications may be made in the spiral roll without departing from the spirit and scope of the invention as set forth in the following claims.

I claim:

1. A spiral roll for the kink-free attachment of the spiral s 'ng of the oscillating system of a clockwork, comprising a circular cylindrical supporting surface for the inner end piece of the spiral spring to be fixed to the spiral roll, a releasing edge terminating said circular cylindrical supporting surface and after which said spiral spring expands according to its natural shape at a spacing from said spiral roll, and said roll having a mounting hole for placing said spiral roll over the balance wheel shaft of said oscillating system, the axis of said mounting hole being parallel to the axis of said circular cylindrical supporting surface and passing through the third or fourth quadrant of a right-angled system of coordinates which extends in a plane normal to the axis of said circular cylindrical supporting surface, the origin of which lies in the axis of said circular cylindrical supporting surface, the x axis of which extends through said releasing edge, and the quadrants of which are counted from said releasing edge in the same sense in which the convolutions of said spiral spring become wider, the axis of said mounting hole being spaced from the x axis of said system of (to-ordinates at least substantially /211" times the pitch of said spiral spring.

2. The invention as recited in claim 1, wherein said circular cylindrical supporting surface is formed by the base of a groove formed in said spiral roll.

3. A spiral roll for the kink-free attachment of the spiral spring of the oscillating system of a clockwork, comprising a circular cylindrical supporting surface for the inner end piece of the spiral spring to be fixed to the spiral roll, a releasing edge terminating said circular cylindrical supporting surface and after which said spiral spring expands according to its natural shape at a spacing from said spiral roll, said roll having a mounting hole for placing said spiral roll over the balance Wheel shaft of said oscillating system, the axis of said mounting hole being parallel to the axis of said circular cylindrical supporting surface and passing through the third quadrant of a right-angled system of co-ordinates which extends in a plane normal to the axis of said circular cylindrical supporting surface, the origin of which lies in the axis of said circular cylindrical supporting surface, the .r axis of which extends through said releasing edge, and the quadrants of which are counted from said releasing edge in the same sense in which the convolutions of said spiral spring become wider, a first recess interrupting said circular cylindrical supporting surface in the first quadrant of said system of co-ordinates, said first recess being adjoining said releasing edge, and a second recess interrupting said circular cylindrical supporting surface in the third quadrant of said system of co-ordinates.

4. The invention as recited in claim 3, wherein the axis of said mounting hole is spaced from the x axis of said system of co-ordinates at least substantially /27r times the pitch of said spiral spring and is spaced from the y axis of said system of co-ordinates no more than half the pitch of said spiral spring.

References flirted in the file of this patent UNITED STATES PATENTS 2,057,642 Eddison et a1 Oct. 13, 1936 2,39l,8l6 Bennett Dec. 25, 1945 

